Number of parked messages

I am trying to figure out a way of getting the number of parked messages. Is there a way to get that count? So far i manage to get the last event in the parked stream.

http://localhost:2113/streams/%24persistentsubscription::group1-parked/head/backward/1

and then reading the metadata

http://localhost:2113/streams/%24persistentsubscription::group1-parked/metadata.

Does anyone know how do I get the exact count?